Dynamic disorder inBaTiO3epitaxial films

Evidence for Strain-Induced Ferroelectric Order in Epitaxial Thin-FilmKTaO3

“…The relaxorlike properties evidenced in epitaxial films of ðBa; SrÞTiO 3 [13] indicate a presence of the short-range-order region in the phase diagram for this FE, too. Similar short-range order found in epitaxial films grown by different methods and in different laboratories [9,12,13] suggests its fundamental origin, not related to technological imperfections. Studies of dynamic effects might give a clue to understanding this origin [12,28].…”

“…In relaxor PbMg 1=3 Nb 2=3 O 3 , the derivative ðTÞ decreases with decreasing T below T m [20]. Similar behavior is found in relaxorlike BaTiO 3 films [12]. Importantly, in normal FEs, the derivative ðTÞ increases weakly on cooling below T m [ Fig.…”

“…Importantly, in epitaxial films of perovskite-type relaxors, strain has been found to enhance relaxor features, but not to induce the FE state [11]. Unexpectedly, the relaxorlike properties have been observed also in epitaxial films of FE BaTiO 3 and FE ðBa; SrÞTiO 3 [12,13].…”

“…Such a region might also exist in epitaxial films of FE BaTiO 3 . In BaTiO 3 films, the FE order has been demonstrated for s ¼ À2:1% [8], s ¼ À1:3% [7], and s ¼ 0:58% [27], with the relaxorlike properties found for s ¼ À0:7%-0% [12]. The relaxorlike properties evidenced in epitaxial films of ðBa; SrÞTiO 3 [13] indicate a presence of the short-range-order region in the phase diagram for this FE, too.…”

“…To prove the FE behavior below T m , the shape of the dielectric peak is analyzed using the derivative ðTÞ of inverse permittivity [12,20] (or that of inverse capacitance density) [ Fig. 3(b)].…”